Not my experience at all with premiums. Maybe cup and core bullets, but I haven't seen it.
What matters the most with most cup and core bullets is impact velocity. If it's too low, they don't open much or at all. I had a buddy finish off a 3 yr.old buck with a neck shot at 300 yds. with a .300 Savage. The 150 gr. Sierra broke the neck, ok, but didn't expand to any noticable degree. Good thing it hit just right.
Pushed too fast and they come apart. The small buck I killed with a 7mm magnum at 300 yds., was hit in the very top of the back. Too high to hit ther spine. Ripped a gash about four inches wide as it came apart. Even at 300 yds., the 140 gr. Sierra was still moving a little too fast.
In contrast, the Nosler Partitions I've used under similar circumstances have always held together, penetrated and expanded very rapidly. Even at really close ranges, like 40 ft. with muzzle velocities of 3400 fps., as well as over 400 yds. and muzzle velocxites of only 2680 fps. In both instances, the bullets went all the way through and left very good wound channels. Odviously a much wider range of performance. E
